Can't connect to my friend In Halo 3?

Halo 3 matchmaking works fine. I can join any of my friend's parties, except for one friend. We have tried for months to join each other with no luck. It even did this back in Halo 2. He and I BOTH have open NATs. I have set it up correctly as far as I know. When we run the the network test in the 360 dashboard it says open NAT (for the both of us). It also says we have open NAT in Halo 3. When we try to connect to eachother, we get the error something like, "Network connection failed. This may be due to router incompaitibilty, you're NAT is set to OPEN, which is the most compatible" It says this on both of our 360s.





We live in the same city and are on the same ISP, if that makes a difference. However, I am able to connect to everyone else who is on that ISP in my area...





Any advice or solutions?

Can't connect to my friend In Halo 3?
Hmmmmmm...


everything seems to be okay. Double-check everything first and make sure every little detail is working correctly, as this can be a minor thing. As for wireless link-up, check your instruction booklet, if the problem persists, it can't hurt to contact the company in charge of making the product and ask for their assitance.